title: Fine structure of the cell wall of the cyanobacterium Microcoleus vaginatus (Vauch.) Gomont.
abstract: The organization of the cell wall of Microcoleus vaginatus (Vauch.) Gomont is described. The four layered wall possesses an unusual layer 2 (mucopolymer containing layer). This layer is 20 nm thick near the crosswall, but abruptly increases in thickness to 90 nm away from the crosswall. In many filaments a perforated sheet 20 nm in thickness was observed on the face of layer 2 which is toward the plasma membrane. It is suggested that this sheet represents an area of mobilization of mucopolymer from layer 2. Electron dense deposits in the cytoplasm or in layer 1 are sometimes observed in association with the developing crosswalls. Junctional pores 12.6 nm in diameter, and spaced 19 nm apart were observed in the longitudinal wall on each side of the junction between the cross and longitudinal walls. Other pores through layer 2 were also observed. These 10 nm pores in the longitudinal wall were randomly arranged (15 to 40 nm apart) and were located on each side of the crosswall up to a distance of 0.6 micrometer from the junction. The relationship between the thickness of layer 2, and the diameter of M. vaginatus and other blue-green algae is discussed.
mesh_terms: D002473:Cell Wall / Q000648:ultrastructure; D000458:Cyanobacteria / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008954:Models, Biological